Section 136 (Anti-Lock Brake System): Diagnosis: Notes

WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 1996 Chevrolet Chevy Van, 1995 GMC Vandura Special, 1995 GMC Vandura, 1995 GMC Rally Camper Special, and 1995 GMC Rally. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Use of Tech 1 scan tester is recommended but not required.

The Brake Pressure Modulator Valve (BPMV) contains a self-diagnostic capability to detect system failures. When a fault code is set, the BPMV may disable 4WAL system and illuminate ANTI-LOCK light for duration of ignition cycle. Fault codes stored by BPMV can be displayed using Tech 1 with appropriate cartridge.

Before diagnosing 4WAL system, perform a comprehensive visual inspection of system by checking wiring harness connectors for looseness and harness routing (pay particular attention to wheel speed sensor wiring harness routing), applicable fuses in fuse block and ground connections. Ensure brake fluid level in master cylinder reservoir is full.

Start 4WAL system diagnosis with appropriate FUNCTIONAL TEST under TROUBLE SHOOTING CHARTS . If failures are found during FUNCTIONAL TEST, you will be directed to enter diagnostics to retrieve codes or perform symptom diagnosis. FUNCTIONAL TEST may indicate 4WAL system is functioning properly.